Fix unicode test case
Set 'encoding' at the beginning of the script (using a 'magic' Ruby comment), so
that the strings are encoded correctly. The test case now passes for Ruby 1.8 and 1.9.
Also changed class name from 'TC_Output' to 'TC_Track'. The old name collided with
the class defined in '14_output.rb', so that test case wasn't running. Only noticed
when testing with Ruby 1.9, so not sure how long that test has been skipped.